Lithographic printing.



entrain s'rnrns PATENT onnicn,

MARCEL ANDRE JULLIEN AND EMILE LOUIS DESSOLLE, OF LEVALLOIS-PERRET, FRANCE.

LITHOGRAPI-IIC PRI1\TTING.

Specification of Letters latent.

Patented Jan. 21, 1908.

Application filed November 15- 1905. erial No. 287549.

metal plate intended to replace the ordinary,

lithographic stone in printing, and is specially adapted to that purpose, owing to its electrolytic structure, seen from the metallurgical point of view.

The invention relates, moreover, to the method of using the said plates.

This use of the special form of metal sheets, or plates makes it possible to do away with the ordinary lithographic stones which are heavy, cumbersome, expensive and fragile, and also to make use of rotary presses'for printing. It also does away with the use of sheets or plates of Zinc, aluminium or other rolled metals, which have already been tried, and the use of which had to be limited to a very large extent owing to the difficulty of drawing on their surfaces, and also owing to their quick oxidation, which by affecting their sharpness, considerably reduces the number of copies that can be taken, and makes it impossible to keep them for subsequent printing.

According to this invention thin sheets of suitable thickness and size are used, made of one metal or of several superposed metals,

obtained in an electrolytic way, or sheets of metal obtained by ordinary metallurgical processes, on which the same, or other, metal is electrolytically deposited, this deposit be ing specially made for the purpose of obtaining a sufficiently thick, dull and grained surface, on which drawing can be executed perfectly well and which are suitable for lithographic transfer.

In order to prevent work executed on the surfaces of these sheets from undergoing any modification of the kind which takes place on the surfaces now used, other than stone, these surfaces areconstituted by a precious metal, such as silver, gold, etc.

When it is desired to use such a'plate or sheet on a rotary press, the sheet is rolled on, and fixed to the cylinder by means of a device similar -to those now used.

Experience has proved that by means of such sheets covered with an electrolytic deposit of precious metal, prints equal to or better than those made from stone can be obtained.

In order to execute a transfer on the electrolytically prepared metal sheet, it is n ecessary, as for stone, to prepare the surface by means of solutions giving a suitable chemical reaction, so as to enable a large number of copies to be printed.

The operations take place in the following manner:

1. The sheet is carefully cleaned with pure alcohol.

2. The drawing is transferred in the same manner as to stone.

3, The whole is then washed with a very weak solutionof nitric acid having mixed therewith powdered carbonate of lime, to clean up the transfer and prepare it for the application of gum. The presence of lime carbonate in the weak nitric acid produces the evolution of carbon di-oxid which causes local movements or currents of the weak acid and increases the efficiency of the actionof the said acid. After the transfer has been treated with the acid for about two minutes it is washed with water to remove all traces of acid and dirt, after which it is gummed strongly and dried.

4. The sheet is then inked with stiff color by means of a hand roller, in the same manner as a stone.

Subsequently a little talc and powdered resin can be added, adding a little American potash to the water for washing, and finally the whole is strongly gummed.

As soon as the work is dried, the transfer is ready to be secured to the printing machine, and prints of great fineness without any blurred or exaggerated portions can be obtained in large numbers.

After the printing, the transfer can be kept for subsequent printing at a distant date, as the metallic surface used is inoxidizable.

If it is desired, on the contrary, to use the sheet for a new transfer, it is easy to remove the first transfer without scraping, using pumice stone or the expensive graining which is necessary in the case of the stones and metals at present em, loyed.

The'procedure is as fdi the ink by means of turpentine essence. 2. Wash carefully. 3. Rub out the transfer by means of a concentrated solution of Amerilows :1. Remove can potash applied to a pad with a little rotten stone in order not to damage the surface, until the picture has completely disappeared, and then wash carefully. 4. Wash with a solution of diluted sulfuric acid, and finally, if necessary, with a very weak solution of bichromate of potash. The plate is then ready for a new transfer.

It is obvious that instead of the solutions indicated, any other solutions, alternately basic and acid, can be used which are adapted to fulfil the same object.

Having thus described the nature of our invention and the means for carrying out the same, we declare that what we claim is:

A method of producing a lithographic printin plate which consists in subjecting a meta plate having an electrolytically deosited surface of precious metal of granulated structure. to a cleaning agent such as alcohol, applying a transfer to the cleaned surface, washing said surface with a mineral acid containing a solid adapted to combine therewith with the evolution of carbon dioXid gas, and finally preparing said surface for printing in the manner practiced in the case of a lithographic stone, substantially as described.

In testimony whereof we have affixed our names to this specification in the presence of two subscribing witnesses.

MARCEL ANDRE JTILLIEN. EMILE LOUIS DESSOLLE. Witnesses:

JU Es LHERMITZ, HENRI VIGNAUD. 

